.mixin1(@col,@bgc,@bot,@sdw){
    width: 50px;
    height: 50px;
    color: @col;
    background-color: @bgc;
    border-radius: 50%;
    text-align: center;
    line-height: 50px;
    position: fixed;
    right: 20px;
    bottom: @bot;
    z-index: 999;
    box-shadow: 1px 1px 1px @sdw;
    cursor: pointer;
}